Option (a) is correct

SI = (p*r*t)/100

Simple interest in one year = (50000*5*1)/100

= 2500

So, Simple interest in 10 years = 2500 * 10 = 25000

Now it will added to principal and new principal = 50000 + 25000 = 75000

For double the principal short amount = 100000 – 75000 = 25000

Now Let 25000 interest can be gained on 75000 principal in 't' years.

So, 25000 = (75000*5*t)/100

t = 62/3 years.

Hence total time = 10 + 62/3 = 162/3 years.

विकल्प (a) सही है

SI = (p×r×t)/100

एक वर्ष में साधारण ब्याज = (50000×5×1)/100 = 2500

तो, 10 वर्षों में साधारण ब्याज = 2500 × 10 = 25000

अब इसे मूलधन में जोड़ने पर नया मूलधन = 50000 + 25000 = 75000

दोगुनी मूलधन के लिए = 100000 – 75000 = 25000

अब 75000 मूलधन पर 25000 ब्याज t वर्षों में प्राप्त किया जा सकता है।

तो, 25000 = (75000×5×t)/100

t = 62/3 वर्ष।

अतः कुल समय = 10 + 62/3 = 162/3 वर्ष